Fix possible use of undefined macros on very old macOS [ci skip]

dln.c

@@ -298,15 +298,15 @@ COMPILER_WARNING_POP
 /* assume others than old Mac OS X have no problem */
 # define dln_disable_dlclose() false
 
-#elif MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_11
-/* targeting newer versions only */
-# define dln_disable_dlclose() false
-
 #elif !defined(MAC_OS_X_VERSION_10_11) || \
     (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_11)
 /* targeting older versions only */
 # define dln_disable_dlclose() true
 
+#elif MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_11
+/* targeting newer versions only */
+# define dln_disable_dlclose() false
+
 #else
 /* support both versions, and check at runtime */
 # include <sys/sysctl.h>

error.c

@@ -666,6 +666,11 @@ bug_important_message(FILE *out, const char *const msg, size_t len)
     fwrite(p, 1, endmsg - p, out);
 }
 
+#undef CRASH_REPORTER_MAY_BE_CREATED
+#if defined(__APPLE__) && \
+    (!defined(MAC_OS_X_VERSION_10_6) || MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6)
+# define CRASH_REPORTER_MAY_BE_CREATED
+#endif
 static void
 preface_dump(FILE *out)
 {
@@ -674,7 +679,7 @@ preface_dump(FILE *out)
         "-- Crash Report log information "
         "--------------------------------------------\n"
         "   See Crash Report log file in one of the following locations:\n"
-# if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6
+# ifdef CRASH_REPORTER_MAY_BE_CREATED
         "     * ~/Library/Logs/CrashReporter\n"
         "     * /Library/Logs/CrashReporter\n"
 # endif
@@ -699,7 +704,7 @@ postscript_dump(FILE *out)
         "[IMPORTANT]"
         /*" ------------------------------------------------"*/
         "\n""Don't forget to include the Crash Report log file under\n"
-# if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6
+# ifdef CRASH_REPORTER_MAY_BE_CREATED
         "CrashReporter or "
 # endif
         "DiagnosticReports directory in bug reports.\n"

thread_pthread.c

@@ -1861,7 +1861,8 @@ native_thread_native_thread_id(rb_thread_t *target_th)
     return INT2FIX(tid);
 #elif defined(__APPLE__)
     uint64_t tid;
-# if ((MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6) || \
+# if (!defined(MAC_OS_X_VERSION_10_6) || \
+      (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6) || \
       defined(__POWERPC__) /* never defined for PowerPC platforms */)
     const bool no_pthread_threadid_np = true;
 #   define NO_PTHREAD_MACH_THREAD_NP 1